The present invention relates to an electromagnetic pulse receiver for a flow meter particularly of great nominal width.
More particularly, it relates to an electromagnetic pulse receiver for a flow meter, in which a measuring wheel which rotates in a measuring chamber carries a magnet device, and a sensor operating in accordance with the Wiegand principle is located outside of a pressure chamber and provided with a plurality of pulse wires which are arranged on a cylindrical outer surface and extend in a longitudinal direction. During rotation of the measuring wheel magnetic pulses are produced and converted in a receiver coil located inside the pulse wires into electrical voltage pulses. The number of these electrical pulses is indicative of a quantity of a medium which flows through a flow meter and is to be measured.
An electromagnetic pulse receiver for a flow meter with smaller nominal width is disclosed for example in the German document DE-OS No. 3,321,952. In this electromagnetic pulse receiver the pulse wires with the receiver coil are arranged in a recess of an end wall of a measuring chamber. Because of this end-side arrangement of the pulse wire sensor, even in the event of minimum counter width a great receiver cylinder having a sufficient diameter is provided which can accommodate a plurality of pulse wires and thereby enables a high resolution in small partial volume. When this principle is used for a counter having a greater nominal width, the receiver cylinder must be made with a greater diameter in correspondence with increased diameter of the measuring wheel. As a result of this, the pulse receiver becomes too expensive and requires too much space. Moreover, the end wall of the measuring chamber which is penetrable by the magnetic field of the magnet arranged in the measuring wheel must have a thick wall because of the increased diameter of the receiver, to provide a sufficient strength. Therefore, the distance between the magnet and the pulse wires becomes too great and as a result of this an unobjectionable operation of the receiver is more difficult or impossible.